1. Field of the Invention
The present invention is directed to novel chewable or dissolvable nutritional supplements in improved forms that optimize absorption of folic acid in humans and other animals, and methods of using said supplements. The nutritional supplements are formulated with folic acid and non-toxic acid neutralizing alkaline compounds in chewable or dissolvable forms which provide highly absorbable or highly bioavailable forms of folic acid.
2. Description of the Related Art
Folic acid deficiency is the most common vitamin deficiency experienced by individuals in the U.S. See USP DI.TM. Drug Information for the Health Care Professional, 18.sup.th Ed., 1988. It is crucial that an adequate level of folic acid be maintained in the body because folic acid plays an especially important physiological role. Folic acid, also known as pteroylglutamic acid and vitamin B.sub.9, plays an important role in cell division, erythropoiesis and protein synthesis, all of which are processes very important to growing tissues. Folic acid is part of an enzyme complex that changes vitamin B.sub.12 into its active form and helps synthesize amino acids into the new DNA required for dividing cells. See Whitney, E. and Rolfe, S., Understanding Nutrition, 6.sup.th Ed., 311 (1993). Folic acid delivered to the body in food is often bound to glutamic acid, but the body prefers to absorb the folic acid in its "free" state. Therefore, folic acid has a low bioavailability. Id.
In fact, only about half of dietary folic acid is available to the body. The Recommended Daily Allowance (RDA) for folic acid takes this low bioavailability into account. For example, in the U.S., the RDA for folic acid is as follows: 150-200 mcg for adult males, 150-180 mcg for adult females, 400 mcg for pregnant females, 260-280 mcg for lactating women and 25-50 mcg for infants and children. See Current Pediatric Diagnosis and Treatment, 13.sup.th Ed., 1997.
Uncooked green vegetables, beans, liver, kidney, yeast, potatoes, cereal, mushrooms and fruit juices are all sources of folic acid. However, the heating of foods will destroy up to 90% of the bioavailable folic acid. See Whitney, E. and Rolfes, S., Understanding Nutrition, 6.sup.th Ed., 314 (1993). Therefore, natural sources of folic acid provide a low bioavailable or poorly absorbable form of folic acid.
Various internal and external factors can result in folic acid deficiencies in both males and females. For example, folic acid deficiency can occur when there is a need for increased cell proliferation, such as that experienced during pregnancy, cancer, blood loss and skin diseases. Folic acid is also very vulnerable to interactions with drugs. Drugs with similar chemical structures to folic acid, can replace folic acid in metabolic pathways. For example, aspirin, antacids, cholestyramine, anticonvulsants and oral contraceptives may interfere with the levels of folic acid in body tissues. Various other factors can also negatively impact folic acid levels, for example, smoking and prolonged stress. Id. at 313.
Further, folic acid is converted into an active form in the lever and is absorbed by the intestinal system. As a result, folate metabolism is vulnerable to any intestinal system disturbance, such as injury to GI tract cells or alcohol abuse. Id.
Regardless of the cause, folic acid deficiency carries serious consequences. Specifically, folic acid deficiency impairs cell division and protein synthesis. Further, folic acid deficiency slows the replacement of red blood cells and GI tract cells. A significant symptom of folic acid deficiency is anemia, including megaloblastic anemia and macrocytic anemia. Id.
The physiological demands for folic acid are elevated when additional stresses are placed upon the body. For instance, due to the increase in cell proliferation during a pregnancy, pregnant women require more folic acid than normal, and are at a greater risk for a folic acid deficiency. Therefore, the recommended intake of folic acid is increased during pregnancy. In view of this increased risk, physicians generally recommend that pregnant women supplement their diet with vitamin and mineral formulations. Folic acid supplementation during pregnancy is believed to reduce the risk of neural tube defects, such a spina bifida, in infants. See Current Obstretics and Gynecology Diagnosis and Treatment, 8.sup.th Ed., 1994. Other teratogenic effects (e.g. birth defects) are linked to underexposure to folic acid or overexposure to folic acid antagonists. See Current Pediatric Diagnosis and Treatment, 13.sup.th Ed., 1997.
Various approaches to increasing the bioavailability of folic acid have been described. Further, numerous approaches for reducing the risk of neural tube defects and other birth defects have also been described in several references.
For example, Nesbitt, U.S. Pat. No 5,569,477, discloses a chewing gum containing various vitamins and minerals, including folic acid. The vitamins and minerals are preferably present in levels prescribed by the U.S. RDA.
Serpelloni et al., U.S. Pat. No. 5,527,542, disclose a process for coating the surface of vitamin and other pharmaceuticals products with Maltitol sugar, to improve the taste and aesthetic appearance of the product. Whether in tablet or form, the products would be intended to be swallowed whole.
Sparks et al., U.S. Pat. No. 4,952,402, disclose a controlled release powder made of microparticles containing an active ingredient, such as vitamins or pharmaceuticals, and a polymer. The powder can be suspended in liquid and maintain its controlled release characteristics for a sustained period of time.
Callingham et al., U.S. Pat. No. 5,028,411, disclose a composition for the buccal or nasal administration of iron, zinc or folic acid to the body. The buccal and nasal sprays and lozenges of this invention are made of a neutral iron(III) complex, which is more effective in the neutral pH of the mouth and nose than in the gastrointestinal tract.
Mehra et al., U.S. Pat. No. 5,733,575, disclose a non-toxic enteric film coating for pharmaceuticals comprising a polymer, a detackifier, a viscosity modifier and an alkalizing agent. The coating prevents the active ingredient from being absorbed by the body until it reaches the intestines.
Briggs et al., U.S. Pat. No. 4,752,479, describe a multi-vitamin and mineral supplement for oral administration containing divalent calcium and magnesium as well as iron. The mineral supplement is adapted to be released in the upper gastrointestinal tract, while the iron component is adapted to be released in the lower intestinal tract.
Vitamin supplements for pregnant women containing folic acid have also been described in various references. Uterwaal et al., U.S. Pat. No. 4,710,38, describe a nutritional supplement for pregnant and breast-feeding women based on milk constituents containing, among other vitamins and minerals, folic acid.
Paradissis et al., U.S. Pat. No. 5,494,678, disclose a multi-vitamin and mineral supplement for pregnant women comprising a regimen of calcium, vitamin D and certain B complex vitamins, including folic acid. This supplement is tailored to maximize fetal development and maternal health during pregnancy.
The Physician's Desk Reference for Nonprescription Drugs describes various vitamin and mineral supplements which contain folic acid. For example, One-A-Day.RTM. Maximum Formula Vitamins and Minerals for Adults, made by Miles, Inc., is a multi-vitamin and mineral supplement indicated as a dietary pill to be swallowed once a day. The supplement contains 0.4 mg of folic acid. See Physician's Desk Reference for Nonprescription Drugs, 611 (9.sup.th Ed., 1988).
vitamins for Women, made by Vitamins for Women, Inc., is a set of vitamin and mineral supplements, one to be taken during the day and the other at night. The supplements contain 400 mcg of folic acid. See Physician's Desk Reference for Nonprescription Drugs, 718 (9.sup.th Ed., 1988).
Theragren Jr..RTM., made by E. R. Squibb and Sons, Inc., is a children's chewable vitamin formula. The chewable supplement contains 0.4 mg of folic acid. See Physician's Desk Reference for Nonprescription Drugs, 705 (9.sup.th Ed., 1988).
Flinstones.RTM. Complete and Bugs Bunny.RTM. Children's Chewable Vitamins, made by Miles Inc., is a children's chewable vitamins dietary supplement. These chewable supplements both contain 0.3 mg of folic acid. See Physician's Desk Reference for Nonprescription Drugs, 610 (9.sup.th Ed., 1988).
The above described folic acid compositions and methods are deficient in that they fail to provide highly absorbable folic acid. Further, the current formulations and methods do not adequately address folic acid deficiency, particularly in individuals with enhanced folic acid requirements, such as women who are pregnant.
Folic acid is poorly absorbed when it is not solubulized in the intestines. In the above described folic acid composition, the folic acid is delivered to the body in dosage forms that leave folic acid in the poorly solubilized state due to the stomach's acidic environment. As capsules and tablets are broken down by the stomach's digestive acids, the folic acid is precipitated and thus converted to a form that is less soluble. Therefore, very little folic acid in a soluble form reaches the intestines. Even the folic acid which does reach the intestines encounters problems with absorption.
As discussed above, folic acid plays an essential role in various physiological processes. Previously-available forms of folic acid do not optimize absorption of folic acid. Accordingly, it would be desirable to provide a nutritional supplement containing folic acid which overcomes the deficiencies of the previously-available folic acid supplements. In particular, there is a need for folic acid supplements which optimize or improve the absorption of folic acid.